1. Field of the Invention
The present invention relates to vehicle passenger safety modules that use pressurized gas from an inflator to deploy an airbag between passengers and the interior of a vehicle in the event of a collision. In particular, the present invention pertains to thrust neutral diffuser/gas guides in an inflator for shipping and handling safety.
2. Background
A typical airbag for a vehicle passenger safety module includes an inflation portion that captures pressurized gas from an inflator, thereby becoming a gas-filled cushion interposed between a vehicle occupant and the interior vehicle surfaces surrounding that occupant. The inflator is ignited electrically in response to a momentum monitor carried in the vehicle.
The inflator has a discharge end that emits pressurized gas into the airbag. An airbag inlet portion directs pressurized gas from the inflator in directions and in quantities that are optimally suited to efficiently inflate the airbag cushion. This sleeve-like inlet portion of the airbag communicates with the inflation portion of the airbag cushion. When the elements of a vehicle passenger safety module are assembled in a vehicle, the inlet portion of the airbag is advanced over and secured to the inflator.
The release of inflation gas from the inflator imposes a substantial amount of reactive thrust, requiring the assembly of the inflator and airbag inlet portion to be securely restrained in the vehicle in which the assembly is employed. The inflation of the airbag cushion neutralizes most of the directional thrust, and the restraint that secures the inflator to the vehicle absorbs the remainder of any thrust.
The thrust caused by igniting the inflator is significant, and can cause an inflator to become a dangerous projectile if not restrained or rendered thrust neutral. Accordingly, if an unrestrained inflator is unintentionally ignited during shipping, handling, or installation an unsafe situation can occur.
Typically, during shipping and handling, before the installation of the assembly in a vehicle, physical restraint against the effects of reactive thrust is absent. As a result, unless the inflator is thrust neutral, the unintended discharge of inflation gas from the inflator can present serious safety concerns.
Hence, it would be an advance if an inflator could be thrust neutral during shipping, handling, and installation, but provide desired inflation characteristics during deployment of a fully-installed airbag module. It would be a particular advance if the inflator could provide a shipping-safe, thrust-neutral feature and desired deployment characteristics without structural modification to the inflator between shipping and deployment.